A Study on Search Processing in Early Vision by Visual Angle and Stimuli Heterogeneity

Abstract

This study aims at confirming the significance of search asymmetry, which appears under the condition of the exchange of target stimulus to distractor items with simple features, and at proposing some new arrangements of the stimuli presented in terms of visual angle and stimuli heterogeneity for examining search processing in early vision. The results obtained were as follows: (1) Search time depended on visual angle, for example, target position of stimuli presentation among distractors, and on heterogeneity in distractor stimuli presentation-search time also depended on the serial self-terminating effect, which appeared in participants when they could not find a target in parallel processing; (2) significant search asymmetry was confirmed by search time under the conditions of applying visual stimuli of lines in 2 kinds of arrangements, parallel and converging; (3) for the evaluation of search processing performance, correct ratio was an important index in addition to search time. Search time reflected a self-terminating effect depending on the condition of stimuli presentation, whereas correct ratio reflected performance accuracy in visual search. The former represents the total processing of human visual search performance and the latter represents human perception accuracy in early vision.